I liked this one. A lot of puzzles, especially in the beginning. Not ALL puzzles though (there is some building, and an largish assault). Plenty of set-piece actions where you can either look for a way to finesse it (there usually is one) or else blast your way through. I think I actually did enjoy the earlier parts more than the last huge battle sequences, but then that may just be my own disposition rather than a flaw in the design itself.
Overall very enjoyable. I'd recommend it to anyone except maybe the gland-stimulate first-person-shooter types.